investigation pursuant to subdivision (b), the Division of Occupational Safety and Health shall, pursuant to Section 147.1 of the Labor Code, develop and present one or more proposed occupational health standards to the Occupational Safety and Health Standards Board in the Department of Industrial Relations, unless the Division of Occupational Safety and Health affirmatively determines, in a written finding within 90 days, that a standard is not necessary to protect the health of an employee who has regular exposure to the hazard for the period of his or her working life. The written finding shall identify the reasons for determining the standard is not necessary and the factual basis for the finding.